The sweeping probe will examine the police department's policies and practices and will specifically explore whether officers routinely use excessive force, officials said at a news conference.

"The road ahead will be difficult," said U.S. Assistant Attorney General Thomas Perez. "This work is not easy, but this independent review is critical to ensuring and preserving trust between a police department and the community it serves." (Read the full statement by Perez in the document viewer below)

In making the announcement, Perez appeared with U.S. Attorney Steven Dettelbach, Cleveland Mayor Frank Jackson, city police Chief Michael McGrath and city Safety Director Martin Flask.

Jackson said he welcomed the inquiry.

Such investigations typically take 12 to 18 months and often result in an agreement, or consent decree, that calls for a federal judge to oversee efforts by a department to reform its ways.

Assistant U.S. Attorney General Thomas Perez announces this morning that the U.S. Department of Justice will investigate the Cleveland Police Department for possible excessive use of force. From left are: Cleveland Police Chief Michael McGrath, Safety Director Martin Flask, Perez, U.S. Attorney Steven Dettelbach and Cleveland Mayor Frank Jackson.

In January, a federal judge approved a consent decree governing New Orleans' police department. The decree resulted from a lengthy Justice Department probe that found a long list of police abuses, including the use of excessive force, unconstitutional stops and searches, and racial discrimination.